Fix <rdar://problem/6206858> [sema] type check @throw statements.

Added a FIXME to handle 'rethrow' check.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64308 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Basic/DiagnosticSemaKinds.def b/include/clang/Basic/DiagnosticSemaKinds.def
index c58c075..4fed944 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.def
+++ b/include/clang/Basic/DiagnosticSemaKinds.def
@@ -846,6 +846,8 @@
      "method %objcinstance0 not found in protocol (return type defaults to 'id')")
 DIAG(error_bad_receiver_type, ERROR,
      "bad receiver type %0")
+DIAG(warn_objc_throw_expects_object, WARNING,
+     "invalid %0 argument (expected an ObjC object type)")
 
 
 // C++ casts
diff --git a/lib/Sema/SemaStmt.cpp b/lib/Sema/SemaStmt.cpp
index 18d9ad6..f4eb22d 100644
--- a/lib/Sema/SemaStmt.cpp
+++ b/lib/Sema/SemaStmt.cpp
@@ -981,9 +981,22 @@
 }
 
 Action::OwningStmtResult
-Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, ExprArg Throw) {
-  return Owned(new (Context) ObjCAtThrowStmt(AtLoc,
-                                          static_cast<Expr*>(Throw.release())));
+Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, ExprArg expr) {
+  Expr *ThrowExpr = static_cast<Expr*>(expr.release());
+  if (!ThrowExpr) {
+    // FIXME: verify the 'rethrow' is within a @catch block
+  } else {
+    QualType ThrowType = ThrowExpr->getType();
+    // Make sure the expression type is an ObjC pointer or "void *".
+    if (!Context.isObjCObjectPointerType(ThrowType)) {
+      const PointerType *PT = ThrowType->getAsPointerType();
+      if (!PT || !PT->getPointeeType()->isVoidType())
+        // This should be an error, however GCC only yields a warning.
+        Diag(AtLoc, diag::warn_objc_throw_expects_object)
+                    << ThrowExpr->getType() << ThrowExpr->getSourceRange();
+    }
+  }
+  return Owned(new (Context) ObjCAtThrowStmt(AtLoc, ThrowExpr));
 }
 
 Action::OwningStmtResult
diff --git a/test/Parser/objc-try-catch-1.m b/test/Parser/objc-try-catch-1.m
index 2e3c5b1..0e8a919 100644
--- a/test/Parser/objc-try-catch-1.m
+++ b/test/Parser/objc-try-catch-1.m
@@ -27,7 +27,7 @@
       return proc();
     }
     @catch (Frob* ex) {
-      @throw 1,2;
+      @throw 1,2; // expected-warning {{invalid 'int' argument (expected an ObjC object type)}}
     }
     @catch(...) {
       @throw (4,3,proc());
diff --git a/test/SemaObjC/try-catch.m b/test/SemaObjC/try-catch.m
index e4c20b7..00f1129 100644
--- a/test/SemaObjC/try-catch.m
+++ b/test/SemaObjC/try-catch.m
@@ -35,3 +35,9 @@
     // the exception name is optional (weird)
     @catch (NSException *) {}
 }
+@end
+
+int foo() {
+  @throw 42; // expected-warning {{invalid 'int' argument (expected an ObjC object type)}}
+  @throw; // FIXME: error: ‘@throw’ (rethrow) used outside of a @catch block
+}